The adverse effects of prolonged sitting are well documented. Prolonged sitting can cause: an accumulation of metabolites; accelerated disk degeneration leading to disk herniation; premature mortality; chronic diseases such as cardiovascular disease, diabetes, and cancer; and obesity (Pope et al., “Spine Ergonomics”, Annual Review of Biomedical Engineering, Vol. 4: 49-68; and, Pronk et al., “Reducing Occupational Sitting Time and Improving Worker Health: The Take-a-Stand Project, 2011”, Prey Chronic Dis 2012, Vol. 9, Oct. 11, 2012).
Height adjustable desks that position a user to stand and work have become popular to assist a user in avoiding these adverse health effects. But prolonged standing also has its drawbacks: back, feet, and leg muscle fatigue leading to injury; chronic venous insufficiency and varicose veins; carotid atherosclerosis; preterm birth; and, joint compression and tearing where the synovial fluid is not circulating and thus reducing the normal lubrication and cushioning of synovial joints, such as knees (e.g. Halim et al, “A Review on Health Effects Associated with Prolonged Standing in the Industrial Workplaces”, IJRRAS; July 2011: 8(1): 14-21).
A user therefore needs to be able to rapidly shift between sitting and standing at their desk throughout the course of their workday in order to avoid these adverse effects while maximizing the benefits of standing. Height adjustable desks are specifically designed for this purpose. Via a user controlled electrical or mechanical mechanism linked to the desk, the desktop will quickly rise to a standing position and lower to a sitting position so as not to interrupt the user's work.
Footrests for use with height adjustable desks also help to alleviate the adverse effects of prolonged standing. The purpose of the footrest is to provide proper biomechanical support of the spine and hips while the user is standing. By raising one leg slightly, the pressure on the lower lumbar discs shifts to the outer pelvis, thus reducing spinal compression leading to disc degeneration. Footrests also provide relief to a user experiencing muscle fatigue in their back, feet and legs from prolonged standing (e.g. Sartika et al, “Investigation of Lower Limb Fatigue on Two Standing Posture”, Jurnal Optimasi Sistem Industri, April 2012: 11(1): 208-213).
Height adjustable desks with unattached footrests are known in the art. For example, a user may purchase a height adjustable desk and a footrest separately, but these footrests require the user to physically move and store the footrest when it is not in use. Additionally, these unattached footrests are normally too high to provide the proper alignment of the spine when the user is standing, which requires raising one leg only a few inches and shifting the user's weight outwardly (i.e. right-left).
A few height adjustable desks with built-in footrests are also known in the art, but the footrests are often: too high in elevation for proper spinal alignment when the user is standing; they do not move automatedly with the desktop movements; and, they obstruct the user's legs when sitting because the footrest is stored in a low position near the front of the desk.
What is needed within the industry of height adjustable desks is a footrest that automatedly shifts from a sitting to a standing position when the desktop is raised and lowered. Footrest adjustment between a standing and sitting position should not require any physical work and time from the user. Additionally, the footrest should not obstruct the user's legs when they are sitting at the desk. And, the footrest should also be appropriate for use with a standing position by being positioned only a few inches off of the ground for the proper biomechanical support of the user's spine, versus footrests for sitting that are the approximate height of the chair to elevate and straighten a user's legs (e.g. see U.S. Pat. No. 7,322,656 issued to Wang). And lastly, the footrest should be hidden from view when not in use.